Project Summary/Abstract Alzheimer's disease (AD) is an irreversible, progressive neurodegenerative disorder that represents the most common cause of dementia in the United States. The link between alcohol use and AD has been widely studied; however, preclinical research is needed to more fully elucidate neurobiological mechanisms that underlie this interaction. As part of the currently funded R37 MERIT award that is focused on molecular mechanisms of alcohol addiction, we evaluated the impact of alcohol drinking on the prefrontal cortex and amygdala neuroproteome in mice. Bioinformatics revealed a striking, and unexpected, major association between alcohol drinking and AD pathology. In both brain regions, tau (MAPT, pTau forms neurofibrillary tangles), amyloid beta precursor protein (APP, cleaved to form amyloid plaques), and presenilin-1 (PSEN1, ?-secretase family, cleaves APP) were identified as the main modulators of alcohol-sensitive protein networks. Moreover, we found that voluntary alcohol drinking is associated with cognitive decline and comorbid anxiety- and depression-like behaviors, which are hallmark behavioral pathologies of AD. Together, these findings suggest that alcohol drinking may increase the magnitude of AD neural and behavioral pathology. To address this hypothesis, we propose to evaluate effects of alcohol drinking on AD-linked neural and behavioral pathologies using a well-validated triple-transgenic mouse model of AD. The 3xTg-AD mouse expresses human forms of the 3 protein-network modulators detected in our studies (MAPT, APP, and PSEN1) and develops amyloid beta (A?) and tau pathologies as early as 4 months of age. To our knowledge, this innovative mouse line has not been studied in the alcohol field leaving untapped potential for discovering alcohol-induced changes in AD pathology. Experiments will first evaluate the impact of 1-month of alcohol drinking on biomarkers recommended in the 2018 NIA-AA Research Framework, including pTau (AT8 and AT270) and A? (40 and 42), and other alcohol-sensitive proteins identified in our studies such as CaMKII?, Heatshock proteins, and calcineurin in AD-related brain regions and cerebrospinal fluid. Second, we will evaluate the cognitive and behavioral impact of alcohol drinking in 3xTg-AD mice. Neural and behavioral experiments will be integrated by correlational analysis to determine if brain region-dependent changes relate to behavioral outcomes in male and female mice, at 4 and 9 months of age. These ages encompass minimal and moderate pathology stages in 3xTg-AD mice, which provides an opportunity to uncover alcohol-induced changes in AD progression. These studies will move the field forward in understanding alcohol as a risk factor for AD. Moreover, by focusing on biomarkers within the NIA-AA Research Framework, this work will integrate with the broader field of age-related neurodegeneration and complement other NIA supported efforts. Increased knowledge of specific pathologies associated with alcohol use in AD has potential to aid diagnosis and treatment.